1. Field of the Invention
The present invention relates to a method and apparatus for pasting a porous structure, such as a plate or strip. In this description, pasting means an operation by which material in a pasty state is made to penetrate a highly porous structure. Pasting operations are used, for example, in the production of electrodes made of cadmium, nickel, zinc, hydrides or lead, some of which may be plastified.
2. Discussion of Background and Material Information
French patent specification FR 2 548 459 discloses the composition and fabrication of a plastified cadmium electrode. Such an electrode is produced starting from an electrode support made of nickel foam about 2 mm thick having pores of mean diameter 0.7 mm, and introducing into the electrode support an active material in paste form made by intimately mixing cadmium oxide, a plastifying agent such as, 3% aqueous polytetrafluoroethylene), an alcohol-based diluent (such as, ethanol in an amount of 0.8 ml/g of cadmium), and a thickening agent that improves softness (such as, methyl cellulose in an amount of 1% relative to the mass of cadmium oxide. This pasting operation is followed by a first rolling operation then a first low-temperature drying. To improve its electrochemical cycling lifetime, this electrode is doped by dipping it in a nickel salt bath, then dried a second time. Lastly, a final rolling operation reduces the thickness of the electrode by half, thus consolidating the and providing improved mechanical properties.